1. Field of the Disclosure
The present disclosure relates to a printing apparatus that includes a friction retard feeder, and more particularly, to an improved nudger system for use in such feeders that employs a self-cleaning nudger roll.
2. Description of Related Art
Nudger rolls are employed in friction feeders to move the top substrate(s) from a stack to a retard mechanism as a result of a net frictional force. The retard mechanism allows a single substrate at a time to pass thorough the mechanism. Included among nudger rolls are some that are constructed from an elastomeric material. These rolls have a failure mode of loss of suitable high friction coefficient due to contamination, paper dust, dirt build-up and wear. As a result, the nudger roll would need to be replaced or manually cleaned with an abrasive material or cleaning substrate. One attempt at addressing this problem a different way is shown, for example, in U.S. Pat. No. 5,348,282 which includes a self-adjusting nudger roll that comprises two rolls held together by a spring with one of the rolls being fixedly attached in a position which while the other acts as a rotating feed roll and simultaneously orbit about the surface of the other roll. The assembly automatically adjusts the normal force on substrates as the requirement of the feed force change and thereby reduces mis-feeds and multi-feeds.
Unfortunately, paper feeding problems created by contaminated nudger rolls are still present.